I tried to use wireshark using a remote logon to a system. This failed with
This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem.
There was an easy fix.
ssh -X u350@10.1.0.5
Use the -X option – simple.
I also saw references to the file/etc/ssh/sshd_config on the remote machine and the file needing X11Forwarding yes
If you use the following in a command window
echo $DISPLAY
it should say something like
localhost:10.0